Research on the Contribution Rate Level and Adjustment of China's Social Insurance System 并列题名：Research on the Contribution Rate Level and Adjustment of China's Social Insurance System Research on the contribution of value added tax of China's manufacturing industry Research on the distribution effect of China's fiscal and taxation system Research on major issues in the integration and improvements of China's social security system Research on the coordinated development of Chinese marine eco-economic system Research on the optimization of rural social endowment insurance system Research on the evaluation of the implementation of the new type of rural social assistance system Research on the contribution and mechanism of education on China's economic growth Research on the construction and policy support of rural elderly care service system